Process for forming glass sheets.



W. G. SHAW.

PROCESS FUR FORNHNG GLASS SHEETS APPLICATION HLED AUG. 12. )915. RENEWED MAR. 7. 1918.

1 ,283, 3 3 3 Patented Oct. 29, 1918.

ATTORNEYS.

W G. SHAW.

PROCESS FOR FORMING GLASS SHEETS.

APPLICATSON FILED AUG-12. t9l5. RENEWED MAR. 7. Hi8

Patented Oct. 29, 1918.

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WITNESS:

, ATTORNEYS.

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PROCESS FOR FORMING GLASS SHEETS.

Specification of Letters Patent.

Patented Oct. 29, 1918.

Application filed, August .12, 1915, Serial No. 45,116. RenewedMerch-I, 19 1 8 eria l lio 221,100.

. i To allavhom it may concern:-

I trating the first part times until-a relatively Y State of which it is employed.

glass by raising is run bac Be it known that. 1, Human G. Sriaw, a

residing atf citizen of the United States, Creighton, in the county of Allegheny and Pennsylvania, have invented a certain new an useful Proc 5 for Forming Glass Sheets of which the following is a specification.

The invention relates to a process for forming glass sheets. The invention has for its primary'objects; thgprovision of a process capable of producing sheet glass of a better finish than that heretofore produced by drawing operations; the provision of a process which can be economically practised and, which will produce glass of any desired degree of thickness; and the provision of a process which can be carried out with a relatively chea and simple apparatus and which will adil flexibility to the plant in The accompanying drawings illustrate the method of practising the invention; Figure 1 being a diagrammatic side elevation view partly in cross-section, illusof the process, Fig. 2 being a similar viewillustrating the second part of the process. Fig. 3 being an enlarged transverse section on the line TIL-J11 of Fig. 2, and Fig. {i being a diagrammatic sectional view illustrating a modification of the process wherein the cylindrical body of glass is held vertically instead of horizontally during the reheating operation.

Fig. 1; 1 is a glass melting Referring to tank containing a body of molten glass; 2

is a truck upon which is mounted for rotation the handle 3 carrying at one end the gathering bar at; 5 is a motor acting through the caring 6 tracli upon which) the truck runs, and 8 1s a; c nti. .natioii of the track 7 mounted upon a vertically movable platform 9.

' The first step in the operation is to bring the parts in the position shown in Fig. 1, The platform 9 is then lowered, thusimmersing the gathering bar t in the glass, at

which tine the motor is operated to rotate The bar isthen removed from the the platform and the-truck kwardto carry the gathering bar out of the furnace. thus: permitting the coating of glass collected thereon to 0001. This operation thiokicylinder 0f 1 red 4t: in

grass sweetene We crane.

vention is concerned,

to rotatethe handle 3; 7 a.

a slot 15 pair of asbestos sheets 16 supported upon 100 V or runs down then 'repeated a number of;

' sr p h s el w the shields, the two some instances it will be desirable to rotate the bar after its removal from the glass and while 7 the bar is being removed from the furnace in; order glass from'running and becoming thicker on the lower side of the bar than at other parts,

and myinvention contemplates the manipulatlon of the bar in any way necessary to secure a uniform coatin of glass upon the bar. If desired, the owermg of the bar might be accomplished without lowering the platform, this of course being immaterial in so faras the process is concerned. If desired. some other transporting the truck may be used, as for instance a In order to prevent the handle 8 from being overheated it is preferably made hollow as indicated in dotted lines. and water-cooled by a culates from the inlet 10 to the far end of the bar and then returns, flowing out of the outlet 11.

After a sufficient body :of gathered onthe the track 7 until it arrives at the portion shown in Fig. 2, at which time'the truck is adjacent: a reheating furnace 12. In order p to facilitate the turning of the handle 3 and the. bar 4 so that the truck need to be switched, the upper portion 13 6f the truck is made to gotaie in a horigoiital' plane with respect to the lowEr part. The reheating furnace 12- is supplied with heat in any desired way such regenerat-ors, the method of supplying heat being immaterial in so far as my present inand the right hand end .of the furnace is provided with a support.

glass has been or rest 14' for the end of the bar 3 so that 95 such bar may be (held in a perfectly horizontal position. Ingthe floor of the turn. 7e immediately below the gathering bar 4 is a (Fig 3), and below this slot. are a metal plates 17. A clamp 18 is also provided operable from the rod 19.

hen the gathering bar has been moved to the position shown in Fig. '2. heat is applied to soften the body of glass on the bar to such 105 'an extent that it will flow or run down by gravity in the form of a sheet, such sheet passing through the slot 15. This sheet flows be ween the hiehlislthen cracked ofl above to prevent the coating of 60 means than How of water which cirbar at the truck is run along itself will notiti as by burners or Y shields 16. 16, w ishie ds r moved together to "1'10 Sh elds serving to carry J7 used instead of a drawing means. The speed at which the sheet is formed and its thickness may also be varied by regulating the temperature in the reheating furnace 12. Various other arrangements might also be gjnployed for taking care of the sheet of lass, and if desired annealing it as formed. The asbestos sheets are preferably employed to retard the rapidity of cooling and soprevent the glass from cracking.

The gathering rod 4 is preferably cored out larger at its ends as indicated at 20 rind 21, in qonder to slightly cool the body of glass at the. points as compared with the central portion. This causes the edges of the glass sheet formed to harden more quickly, coun teracting the natural tendency of the glass sheet to pull in toward the center of the sheet.

This method of forming glass sheets has certain advantages as comparedm-With the processes now employed for drawing glass sheets. One advantage lies in the fact that sheets of any desired thickness may be drawn and the surfaces thereof will be absolutely flat and smooth. Another advantage resides in the superior finish of the glass, such finish being due to the fact that the glass is reheated to the flowing or drawing point and subsequently cooled, the surface of the glass thus being hotter than is the case where the sheet of glass is drawn from the cooled surface of a body of glass as in the present practice. A very perfect body of glass can be collected upon the gathering bar 4a-. since this body of glass is taken directly from the refined glass of the tank 1. Glass can be kept in a much better condition in a melting tank of this character than in the dog houses or extensions from which it is now the practice to draw glass, and there are no very Wide variations of tem erature in the glass tending to spoil its qua ity such as is the case where the drawing occurs from drawin extensions. 'The process also permits of great flexibility in'the plant in which it is employed since as many gathering rods and reheating apparatus can be employed as is necessary to takecare of the output of the main melting tank, the capaclty of the plant being limited only by that of the meltmg tank.

Fig. 4 illustrates a modification in which the gathering bar 4 is reheated in a vertical position in the furnace 22 so t-hatthe glass flows vertically in the form of a cylinder 23 instead of a flat sheet as in the other type of nreans mig t be ai y ndr east a construction. In order to regulate the speed of movement downward a bait 24 may be employed which is made to adhere to the end of a cyl nder and supplied with air to prevent the cylinder from collapsing. This method of operation of course necessitates mechanism for shifting the gathering bar from its horizontal gathering position to the vertical position indicated in' Fig. 4. It will be seen that the generic idea as involved in this type of construction is the same as in the other type, the only distinction bein that the gathering bar is reheated in a di erent position, thus forminga c lindrical sheet instead of the flat sheet of t 1e other type of apparatus. The process is of course capable of being carried out by a great variety of modified types of apparatus, and my invention relates to the broad features of procedure rather than to any particular type of apparatus, the ones shown serving to merely illustrate the practice involved.

\Vhat I claim is:

l. The process of forming glass sheets which consists in gathering a body of glass in the form of a cylinder upon an elongated horizontally positioned member and permitting it to cool, reheating the body of. glass until it flows therefrom by gravity in the form of a sheet, continuing the heating during the flow, and permitting the sheet thus formed to pass into an area of lower temperature and harden.

2. The process of forming glass Sheets which consists in gathering a body of glass upon an-elongated horizontally positioned member and permitting it to cool, reheating the body of glass with the said member in a horizontal position until the glass flows therefrom by gravity in the form of a Hat sheet, and permitting the sheet'tiius formed to pass into an area of lower temperature and harden.

3. The process of forming glass sheets which consists in gathering a cylindrical body of glass upon a bar by repeatedly dipping bar clrcular in cross-section and held hori zontally into a body of glass, rotating the bar and raising it, permitting the coating ofglass to harden and then repeating the'operation until a cylinder of glass substantially uniform "thickness of glass is secured.

5. The process of forming use, which 0.011.-

a glass sheet naaa saa sists in heating the body of glass until the surface is fluid and flows from the body in a sheet, continuing theheating as the flow continues and permitting the sheet thus formed to harden.

- 6. The process of formin a glass sheet from a cylindrical body of g ass, which consists in heating the body of glass until the surface is fluid while the body is held in a horizontal position and flows from the body in a flat sheet, and permitting the sheet thus formed to pass into a cooler medium and harden.

7. The process of forming a glass sheet from a cylindrical body of gilass, which con sists inheating the body 0 glass until the "surface is fluid, while the body is held in a horizontal position and flows from the body 'in a flat sheet, and permitting the no sheet thus formed to pass into a cooler me- .ldium and harden, the temperature of the end portions of the said body being somewhnt reduced as compared with the central 8.11mi roeesfl of forming a glass sheet f5! body of glass, which con- I ll the body of glass until the miiflui nndflows from the body in a M continuing the heating as the flow c0l1- films and permitting the sheet thus formed to hardengradually to avoid cracking.

9. The process. of forming glass sheets which consists in gathering a body of glass upon a cylindrical metal bar by dipping 35 the bar in molten glass, rotating the bar held in a horizontal position all m from the glass topermittllmfl harden, and repeatimLE-he operation until the desired body of g is collected, than reheating the lass until it flows from the body of glass y gravity in the form of a, sheet and permitting the sheet thus formed to pass into an area of lower temperature and harden, the said metal bar being water cooled.

10. The process of forming glass sheets which consists in gathering'a body of glass upon an elongated horizontally positioned member and permitting it to cool, reheating the body of glass until it flows therefrom by gravity in the form of a sheet, and permitting the sheet thus formed to pass into an area of lower temperature and harden,

tension being applied to the sheet to supplement the force of gravity and regulate the thickness of the sheet. y

11. The rocess of forming glass sheets which consists in gathering a body of glass upon an elongated horizontally positioned member and ermitting it to cool, reheating the body of gravity in t e form of a sheet, contm the heating coincident with the flow, an permitting the sheet thus formed to pom into an area of lower temperature and harden, the thickness of the sheet being regulated by varying the intensity of the heat applied,

W. G. SHAW.

ass until it flows therefrom)! 

